Presentation on theme: "Sampling Sampling: Your data is only as good as your field technicians. Jeff Martin, Astrea Taylor, & Nancy Zikmanis."— Presentation transcript:
Sampling Sampling: Your data is only as good as your field technicians. Jeff Martin, Astrea Taylor, & Nancy Zikmanis
Next Phase of the Project Life Cycle 1.PLANNING: 2.SAMPLING: 3.ASSESSMENT: 4.EVALUATION: Plan for data collection using the DQO process Collect data using a SAP and FSOPs Verify that data meets DQOs Make data-based project decisions
What’s the Goal? Sampling & analysis objectives: – Collect representative samples – Obtain accurate and precise analytical data Quality Assurance Project Plan (QAPP) – Laboratory QA/QC program – Field Standard Operating Procedures (FSOPs) (see handout) – VAP does not require QAPPs, but Ohio EPA encourages their use for accurate, representative data
Who Collects the Sample? Field staff, usually not the CP or project manager Field staff must know how to – Collect, handle & manage samples Understand VAP DQOs for sample collection activities Follow FSOPs – Communicate with the lab COCs & VAP Certification Contact lab for help when needed Complete Chain of Custody (COC)
Field versus Lab Error Most error (60 to 80%) associated with environmental sampling and analysis is due to field sampling error rather than lab error Lab QA/QC programs provide strict management and performance control QA/QC for field sampling activities? We need to rely on FSOPs – typically far less stringent than lab requirements
FSOP Purpose? Standard written instructions that document the way sampling activities are performed to – Meet project data quality objectives – Comply with QAPP (if one exists) Promote quality by properly and consistently implementing accepted methodology (Ohio EPA’s TGM, VAP TDCs)
FSOP Recommendations Follow U.S. EPA and Ohio EPA technical guidance documents (Ohio EPA’s TGM, VAP TDCs) Incorporate flexibility into field investigation as it moves forward Solicit input from technical experts and field staff U.S. EPA format: – Guidance for Preparing Standard Operating Procedures (SOPs), EPA QA/G-6 (EPA/600/B-07/001, April 2007)
FSOPs for Sampling In general, three groups of FSOPs: 1.Sampling media (soil, ground water, etc.) 2.Support (decon, field screening, etc.) 3.Transfer of samples from field to lab: QA/QC samples (duplicates, blanks) Sample management (preservation, handling, and shipment) Chain of Custody
Maintaining Sample Integrity from the Field to the Laboratory Important Concerns that Need Addressed by SOPs
Sampling Practices to Avoid Cross-Contamination While sampling, don’t – Smoke or eat – Wear perfume or cologne – Handle fuels, solvents or other chemicals – Touch potentially contaminated surfaces Regularly change sampling gloves, especially before filling sample containers Use disposable or dedicated sampling equipment whenever possible
Sampling Practices for Volatile Organic Compounds (VOCs) For soils, use SW-846 Method 5035/5035A For ground water (Method 8260B), use the low-flow sampling technique Minimize sample agitation and aeration Seal sample containers and place on ice ASAP
Methods 5035/5035A Low-Level Soil VOCs (< 200 ug/kg) Goal is to collect and preserve soil samples in a manner that minimizes VOC loss Studies indicate significant VOC loss from samples collected using the “bulk soil” or “jar” method (Method 5035A, July 2002, p. 46), problem for low-level VOC samples Several options for collecting/preserving low- level VOC samples
Methods 5035/5035A Low-Level Soil VOCs (<= 200 ug/kg) Sample collection options (coring devices): – EnCore™ Sampler (or similar devices): Designed to collect and contain/transport a soil core Sample may be transferred to a 40 ml VOA vial before shipment to lab – Terra Core Sampler™, Powerstop Handle™ and EasyDraw Syringe™ (or similar devices) Designed to collect and transfer soil cores to VOA vials
Methods 5035/5035A Low-Level Soil VOCs (<= 200 ug/kg) Sample preservation options: – Sealed VOA vial on ice (4 o +/-2 o C) Sodium bisulfate (reacts with carbonate in soil) Methanol (dilution factor, hazardous material/waste) Freezing Holding times: – 48 hours on ice (4 o +/-2 o C) in VOA vial from collection to analysis or preservation (field or lab) – 14 days after preservation to analysis
Methods 5035/5035A Low-Level Soil VOCs (<= 200 ug/kg) What specific collection/preservation options should I use? Ohio EPA recommends evaluating: – Need for low-level soil VOC analyses (DQOs?) – Site conditions (carbonate soils? soils with VOCs > 200 ug/kg? very loose or very dense soils?) – Difficulty/complexity of effort for field personnel to collect and preserve samples
Methods 5035/5035A Low-Level Soil VOCs (<= 200 ug/kg) Most importantly, discuss the use of these methods with the laboratory and follow their recommended sampling and preservation procedures Not all laboratories have the same capabilities or preferences Don’t assume your laboratory will be able to accommodate every 5035/5035A option
Methods 5035/5035A Low-Level Soil VOCs (<= 200 ug/kg) Certified Lab (CL) Rule, OAC 3745-300-04(H)(6) states that the CL shall: “Perform analyses in accordance with the laboratory's standard operating procedures and quality assurance program plan approved by Ohio EPA whenever the laboratory produces certified data”
Methods 5035/5035A Low-Level Soil VOCs (<= 200 ug/kg) Phase II Rule, OAC 3745-300-07(D)(3)(a) states that field QA/QC procedures must include a: “Review of the laboratory’s quality assurance program plan and standard operating procedures for consistency with field quality assurance and quality control procedures”
Ground Water Sampling Issues (Reminder) Sample representativeness? Depends on adequacy of well development and sampling techniques: – Adequate well development? – Sufficient stabilization time between development and sampling? – Proper purging and sampling techniques, e.g., adequate purging prior to sampling? Refer to Ohio EPA’s TGM Chapters 6 and 10
Ground Water VOC Samples Filling 40 ml VOC vials with ground or surface water (zero headspace): – Fill slowly (100 mL/min) to minimize agitation and aeration – Form a meniscus and then slowly screw on cap to seal the sample – Check for bubbles by inverting vial and gently tapping it – Collect at least two vials for each sample
Ground Water VOC Samples Air bubbles in 40 mL vials may be caused by – Insufficient meniscus when sealing the vial – Degassing after sample collection or during sample shipment – Reaction between the sample and preservative (HCl) Air bubbles do not necessarily invalidate the sample – U.S. EPA studies indicate that bubbles smaller than ¼- inch (pea-sized) do not adversely affect the sample
Ground Water VOC Samples If air bubbles are present in a 40 mL VOC vial immediately after sample collection… – Discard vial and collect another sample using a new vial – Don’t re-open and “top off” the vial, this may compromise the sample through Additional exposure to ambient air Loss of preservative
Ground Water VOC Samples If air bubbles are noticed in a 40 mL VOC vial during sample cooler packing… – Recollect the sample if the bubble is ¼-inch (pea- sized) or greater in diameter – Otherwise, submit the sample to the laboratory If sample reacts with preservative, may need to collect an unpreserved sample
Quality Assurance/Quality Control (QA/QC) Minimize – Sources of sampling and analytical error – Potential cross-contamination Maximize – Sample representativeness – Analytical data accuracy and precision
VAP Phase II QA/QC Procedures OAC 3745-300-07(D)(3) Review lab QA/QC procedures – are field QA/QC procedures consistent? QA/QC procedures, not limited to the following: – Equipment decontamination – QA/QC samples – Field instrument calibration – Documentation and record maintenance – Sampling handling, preservation and holding times – Chain of custody
QA/QC Samples Sample Type: Trip Blanks Equipment (Rinsate) Blanks Field Blanks Filter Banks Duplicate Samples When to Submit: One (1) per sample cooler, VOCs only If non-dedicated, non-disposable sampling equipment is used Needed based on field conditions Recommended for field filtering One (1) per 20 samples, typically not collected for soil (due to soil matrix heterogeneity)
QA/QC Samples Matrix Spike / Matrix Spike Duplicate (MS/MSD): – Fill all containers that the lab provides (if four 1-L jars are required, don’t return only two) – Don’t use the most contaminated sample for the MS/MSD (may adversely affect the lab QA/QC results) – Follow the lab’s advice for the MS/MSD and other QA/QC samples (they know what they need)
Sample Management: Preservation Prevents physical and chemical changes to sample during transportation and storage Maintains representative constituent concentrations by – Reducing volatility – Preventing hydrolysis – Retarding biodegradation
Sample Management: Preservation Methods generally used – pH control (add strong acid or base) – Chemical addition (stabilization other than pH control, e.g., Na 2 S 2 O 3 ) – Temperature control (cool to 4 o +/- 2 o C) – Protection from light (amber glass sample containers) Field staff need to understand the purpose of preservation and methods
Sample Management: Preservation Preservatives may react with sample – VOC ground water sample containing carbonate minerals reacts with HCl preservative – Solution: collect an unpreserved sample Sample holding time will be significantly shorter Field staff need to inform lab (must understand the relationship between preservation and holding time requirements)
Sample Management: Preservation Use pre-preserved sample containers or add preservatives in the field? – Most labs provide pre-preserved sample containers – May want to carry additional preservative in the field – Adding preservatives to containers in the field presents additional health & safety concerns (field staff need to be aware of potential hazards)
Temperature control – recommend using ice rather than ice substitute (“blue ice”) – Generally less effective at maintaining the required cooler temperature – Potential source of chemical cross-contamination Propylene glycol Styrene Ammonium chloride
Sample Management: Preservation Use sealable plastic bags to contain ice – Avoid immersing sample containers in water (damaged labels, cross-contamination) – Avoid leaking coolers; also use plastic cooler liner (or commercial shipper may not deliver) – About 1/3 of cooler should be ice – Avoid the use of “blue ice”
Sample Management: Preservation Verification of proper temperature preservation: – Presence of ice in cooler – Measurement of internal cooler temperature – Temperature blank Recommended One per cooler Don’t encase in ice or freeze
Sample Management: Containers & Labeling Containers: – Specifications per analytical methods (SW-846) – Generally provided by lab Stockpiled containers from previous projects? Not recommended: – Loss of preservatives – Cross-contamination issues – Inconsistency with current project lab
Sample Management: Containers & Labeling Labels may be completed in field or (mostly) pre- populated by laboratory Labels should be waterproof and securely affixed to each sample container – Permanent marker or ink (legible if wet) – Protect completed labels with clear tape (except for pre-weighed containers) Recommend completing and affixing label after sample container is filled
Sample Management: Containers & Labeling Label information – Sample identification (per FSOP?) – Date and time collected (AM/PM or military time) – Analytical methods/constituents requested Field staff need to be familiar with methods and their respective constituents – Preservatives – Name or initials of sampler
Sample Management: Shipping Use coolers to ship samples (temperature preservation requirements) Seal ice in plastic bags, use cooler liner Ship containers upright Use packing to protect glass containers, e.g., bubble wrap, styrofoam, etc. Deliver to laboratory via commercial carrier (UPS, FedEx, etc.) or courier
Include the chain of custody (COC) form in the cooler (in a sealed plastic bag) Use an individual COC for each cooler rather than a single COC for multiple coolers – What if the cooler with the COC doesn’t arrive at the lab with the other coolers? – If any cooler in a multiple cooler shipment under a single COC exceeds temp requirements, samples in all coolers will be flagged for temp
Sample Management: Shipping Regulations (DOT), requirements (shipper) – Hazardous materials (LNAPL, methanol)? – Cooler weight? – Type of tape used, cooler labeling? Securely seal cooler Affix custody seal with protective tape
Sample Management: Shipping Shipping method depends on holding times – Hexavalent chromium? – SVOCs by 8270? – Unpreserved VOCs by 8260? Recommend sampling constituents with short holding times last Important for field staff to understand analytical methods and holding time requirements
Sample Management: Shipping Using a commercial shipper? – Should know drop off locations and business hours before sampling – Call locations to verify, just don’t rely on internet Saturday delivery? – Complete appropriate shipping forms – Call the lab to confirm deliver location
Chain of Custody (COC) COC form: critical communication between field samplers and the laboratory Technical and legal record of samples collected, analyses requested and sample custody Field staff must understand how to properly complete COC forms – what does this mean?
Chain of Custody (COC) Field staff should understand the following to properly complete COC forms: – Project and contact information – Sample ID nomenclature – Analytical methods: Method numbers/references Container types and volume requirements Preservative requirements Holding times
Chain of Custody (COC) Field staff should understand the following to properly complete COC forms (continued): – QA/QC samples (trip blanks, duplicates, etc.) Type and quantity needed How to designate/record on form – Information to include as comments or notes Detection limit or certification requirements (VAP) Highly contaminated samples or other matrix issues Special sampling handling/processing requirements
Review for accuracy and completeness Don’t forget to sign COC with date & time Retain a copy before shipping samples Commercial carriers (e.g., UPS) will not sign a COC – Ohio EPA recommends retaining a copy of the shipping form for documentation of sample custody during transportation
Laboratory Interaction Field staff need a lab contact to address: – Questions about method requirements (e.g., preservation, holding times) – Questions about VAP certification – Need for additional sample containers or supplies – Sample matrix concerns (highly contaminated samples, unpreserved samples) – Weekend delivery (sample receiving)
Laboratory Interaction In most cases, the lab is a contractor retained by the consultant Both the consultant and lab have common objectives: – Collect representative samples – Obtain accurate and precise analytical data Mutual understanding, cooperation, and tact will greatly facilitate these objectives
Vapor Intrusion (VI) Sampling & Analysis Background: Has been recognized as a potential pathway of contamination for almost 20 years. In the late 1980s, the first vapor intrusion studies were carried out to evaluate potential health effects from chronic exposure to volatile organic compounds. For labs, this has created an upward trend in the number of ambient air, indoor air, soil gas and sub-slab samples submitted each year for volatile organic compound (VOC) analyses.
The primary compounds of concern are often chlorinated VOCs. Trichloroethene (TCE) and tetrachloroethene (PCE), in particular, are common targets of the investigations due to the health risks associated with these compounds and their breakdown products. Vapor Intrusion (VI) Sampling & Analysis
Sample Collection… Silicon-lined canister (Silonite ® ) Tedlar Bag Varying sizes for GRAB v. TIMED SamplesGRAB Sample only
Canister Cleanliness – HOW CLEAN IS CLEAN? Should you request a “Certificate of Cleanliness” for each canister?
Laboratory Analysis: USEPA Method TO-15 The most frequently requested method for the analysis of VOCs for the range of air samples associated with vapor intrusion investigations. A wide range of compounds (40 to 60) may be analyzed by EPA TO-15 including alkanes, alkenes, aromatics, halogenated VOCs, ketones, esters and some alcohols. (Some aldehydes and sulfides may also be evaluated using this method.)EPA TO-15 Some variation among commercial environmental laboratories in the compound lists (must be specific when communicating with lab). Results reported in μg/m3, ppbV, or both. YOU SHOULD REQUEST BOTH!!! Compound lists can usually be tailored to meet project-specific objectives.
Summary Points Communicate:>Talk to the lab about equipment/canisters Grab v. Time Integrated. >Discuss reporting units – ASK FOR BOTH ug/m 3 and ppbv. >Discuss most appropriate method – TO-15 or TO-15 SIM. >“Certify” each canister? Or accept “batch” decon? >Verify that lab has CURRENT VAP CERTIFICATION for the analysis.
Summary Points Communicate: >Talk to the lab about equipment/canisters Grab v. Time Integrated. >Discuss reporting units – ug/m 3 and ppbv ASK FOR BOTH! >Discuss most appropriate method – TO-15 or TO-15 SIM. >“Certify” each canister? Or accept “batch” decon? >Verify that lab has CURRENT VAP CERTIFICATION for the analysis.
Any additional questions or comments? Thanks for your time and attention!